I have used CL for years, Lucky. I have neither heard of anything untoward happening in our area nor have had any personal "surprises" myself. There are bad apples everywhere though.
I lined the inside of my sliding doors with solar blanket material and also have a roll of it outside and above the doors. I let the blanket down when we are predicted to have extreme cold with wind out of the north. My sliding doors face due north. In my opinion you will never make your GH a completely sealed unit unless you want to build something like my solarium.
